Effective sensory modality activating an escape triggering neuron switches during early development in zebrafish

Area of Science:

• Neuroscience
• Developmental Biology
• Sensory Systems

Background:

• Developing nervous systems integrate diverse sensory signals for complex behaviors.
• Zebrafish escape behavior provides a model for studying sensorimotor circuit development.
• Mauthner (M) cells are crucial for fast escape responses in mature fish.

Purpose of the Study:

• To investigate how developing sensory inputs are integrated into sensorimotor circuits during zebrafish escape behavior.
• To understand the developmental timeline of auditory/vestibular (AV) and head-tactile stimulus integration.
• To elucidate the role of Mauthner cells in mediating this developmental sensory switch.

Main Methods:

• Examined zebrafish escape behavior across developmental stages (45-170 hours postfertilization).
• Utilized otic vesicle (OV) lesioning to block AV input and trigeminal ganglion (gV) ablation to block head-tactile input.
• Employed laser ablation of Mauthner cells and calcium imaging to assess M-cell activity during escape.

Main Results:

• Fast escape latency decreased with development.
• Before 75 hours postfertilization (hpf), head-tactile stimuli initiated escape, while AV stimuli did not.
• After 75 hpf, AV stimuli became the primary trigger for short-latency escape, with M-cell firing essential at all stages.

Conclusions:

• A developmental switch in effective sensory input to Mauthner cells mediates the acquisition of AV-induced fast escape.
• This sensory re-weighting refines sensorimotor circuits for adaptive behavioral responses.
• The findings highlight the dynamic nature of sensory integration during neural development.